policy brief

Analysis of Activity Travel Patterns and Tour Formation of Transit Users

research report

Analysis of Activity Travel Patterns and Tour Formation of Transit Users

presentation

Invited Expert Testimony in 2021 on the California ”Heavy Duty Vehicle Sector” to the Joint Informational Hearing of the California Senate Committee on Transportation and Senate Budget Subcommittee 2 on Resources, Environmental Protection, and Energy, on The California Energy Commission’s Clean Transportation Program and California’s Zero Emissions Vehicle Deployment Strategy

Phd Dissertation

Disaggregate Control of Vehicles using In-Vehicle Advisories and Peer-to-Peer Negotiations

Abstract

Traffic advisories to travelers are based upon traffic state information at the link level. This is due to existing infrastructure which sometimes can only provide link-level information. However, the primary justification for providing link-level data is the reluctance of Traffic Management Agencies to consider more detailed traffic state data for operational and safety reasons. However, with the advances in automotive technology, sensing equipment, and the Internet of Things (IoT), we can do better. Research shows that faster and more accurate travel paths can be obtained by using lane data rather than link data. Our contention is that for vehicles to be able to change lanes to improve their travel times, operationally, they would need to enter into Peer-to-Peer negotiations with surrounding vehicles, where they can trade their position in time and space in accordance to their own perceptions of their values of time and satisfaction and possibly in exchange for monetary benefits. Our work is an exploration of this idea. We begin with a simple in-vehicle advisory control policy, partially inspired by the Kinetic theory of traffic. We then move towards an individual-level Peer-to-Peer negotiated lane change framework by first investigating its efficacy by means of microsimulation studies. We then propose an agent-based optimization framework for this system, which minimizes both travel time and the “envy” induced among drivers when they are assigned paths that are inferior to their peers. Numerical results from running our optimization on an illustrative network show that the proposed model converges to both envy-free and system optimum traffic states, even at a net zero budget, meaning this system can be used by transportation agencies without exacting tolls or giving subsidies. Our proposed framework of routing vehicles on a lane to lane basis can only be realized in the field if the mediating agency (TMC, or a mobility service) has accurate information about traffic conditions. We propose multiple algorithms, including a LSTM (Long Short Term Memory) neural network architecture-based framework to estimate traffic states solely using information collected from sensor-equipped probe vehicles, without the need for any other data such as those obtained from traditional embedded loop detectors. 

policy brief

Higher Bus Ridership Unlikely to Increase Community COVID-19 Transmission

Abstract

Public transportation has been blamed for facilitating the spread of COVID-19 in dense, urban areas. As a response to the COVID-19 pandemic, transit agencies have reduced service and implemented mask-wearing mandates and social distancing aboard transit. Some prior studies that address public transportation provide some evidence that negative COVID-19 outcomes are linked to high transit use. One early study of COVID-19 transmission on trains in China found that transmission is also affected by the density of passengers, seat spacing, and length of time traveled with other passengers aboard the trains.

research report

Non-myopic pathfinding for shared-ride vehicles: A bicriteria best-path approach considering travel time and proximity to demand

policy brief

Non-myopic pathfinding for shared-ride vehicles: A bicriteria best-path approach considering travel time and proximity to demand

research report

Software and Hardware Systems for Autonomous Smart Parking Accommodating both Traditional and Autonomous Vehicles

policy brief

Software and Hardware Systems for Autonomous Smart Parking Accommodating both Traditional and Autonomous Vehicles

Phd Dissertation

Understanding the Travel Behaviors and Activity Patterns Using Household-based Travel Diary Data: An Activity Space-based Approach in a Developing Country Context

Publication Date

March 1, 2021

Author(s)

Abstract

Measuring the geographic extent of travel-activity patterns is important to develop our knowledge on potential and actual activity spaces around individual travel routes and activity locations which will enrich our understanding of human activities. Although a handful of studies integrate activity space within the travel behavior analysis in Europe and U.S. context, few studies have measured the size, structure, and implications of human activity spaces in the context of developing countries. To address these concerns, this dissertation examines the impact of land-use characteristics, socio-demographics, individual trip characteristics, and personal attitudes on travel-activity based spatial behavior in Dhaka, capital city of Bangladesh. Two methods-shortest-path network (SPN) and road network buffer (RNB) were used for calculating activity space in a geographic information system (GIS). First, a household-based travel diary pilot survey was carried out in 2017. Pilot data shows some specific socio-economic and travel differences across two study subareas. Results of this essay help to understand the differences between travel and activity space patterns by study subareas and population subgroups and give specific directions in terms of survey sampling and methodology for the full study to identify most suitable models, sets of indicators, and measurement techniques. Based on lessons learned from the pilot study, a weeklong household-based travel diary survey was conducted in 2018. Multiple Regression Analysis (MRA) results show that mainly land use characteristics are found to be consistently significant predictors of both individual and household activity space size. In this dissertation, Exploratory and Confirmatory Factor Analysis (EFA and CFA) are used to identify attitudinal factors to influence spatial behavior. Household accessibility to different facilities was assessed under this essay using RNB measure. Positive correlations are found between the area and number of all opportunities except open space facility. While examining heterogeneity in activity spaces, results indicate that activity spaces vary from day to day. To further analyze the impact of different indicators on this variability, Panel Regression Model (PRM) is used. My findings help transport planners, researchers, and policy makers to reshape land use policies while keeping in mind human accessibility and activity space variability issues.